configure.ac: Fix typo in enable flag description

Change-Id: Ida390c50379a429a4b42434e32954eeb832a11ff
diff --git a/configure.ac b/configure.ac
index 478da9b..5e17c7a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -312,7 +312,7 @@
 	)],
 	[force_io_select=$enableval], [force_io_select="no"])
 AS_IF([test "x$force_io_select" = "xyes"], [
-	AC_DEFINE([FORCE_IO_SELECT], [1], [Force the use of select() instaed of poll()])
+	AC_DEFINE([FORCE_IO_SELECT], [1], [Force the use of select() instead of poll()])
 ])
 
 AC_ARG_ENABLE(msgfile,